Morphological descriptions of the egg and the three larval instars of Podallea vasseana Navás are presented. Morphological differences between the larvae of P. vasseana and P. manselli Aspöck & Aspöck are noted, and aspects of their biology are discussed.

The scale insect genus Calycicoccus Brain has a single described species, C. merwei Brain, which is endemic to southeastern South Africa. Females of C. merwei induce small, mostly conical galls on the foliage of their host tree, Apodytes dimidiata E. Meyer ex Arn. (Icacinaceae), which has a wider, mostly coastal distribution, than that currently known for the scale insect. Calycicoccus has been placed in the family Eriococcidae and may be related to the South American genus Aculeococcus Lepage. No other native eriococcid species have been described so far in South Africa, although the family is diverse in other Gondwanan regions. This paper summarizes the biology of C. merwei, redescribes the adult female, describes the adult male, the second-instar female and the first-instar nymphs for the first time, and reconsiders the phylogenetic relationships of the genus. The adult female is shown to have unusual abdominal segmentation, in that segment I is present both dorsally and ventrally, but a segment is absent ventrally on the middle abdomen. First-instar nymphs are sexually dimorphic; males have a larger and relatively narrower body, larger mouthparts, longer antennae and legs, and more thoracic dorsal setae compared with females. Molecular data from nuclear small-subunit ribosomal DNA (18S) and elongation factor 1 alpha (EF-1α) show C. merwei to have no close relatives among the Eriococcidae sampled to date. Instead, the Calycicoccus lineage is part of a polytomy near the base of the Eriococcidae. Molecular dating of the node suggests that the Calycicoccus lineage diverged from other eriococcids more than 100 Mya. These data support the placement of Calycicoccus as the only genus in the subfamily Calycicoccinae Brain.

The status of the sarcophagid fly, Wohlfahrtia pachytyli (Townsend) (Diptera : Sarcophagidae), a facultative parasite of the brown locust, Locustana pardalina (Walker), in the Nama-Karoo biome, is reviewed. Information on the distribution, life cycle and larviposition of this ubiquitous flesh fly is presented. As facultative parasites, flies deposit microscopic larvae on the immobile bodies of locusts while they undergo ecdysis. Larvae enter the body cavities, consume the entire inner body contents and kill the locusts. Alternatively, the fly behaves as a saprozoic scavenger, attracted to decaying flesh and faecal matter. With parasitism rates of 0.1 % for fifth instar brown locust hoppers and 6 % for brown locust adult fledglings in the field, the impact of these facultative parasites on gregarious brown locust populations was low. However, a sharp increase of 37 % was registered after 48 hours when brown locust hopper bands, sprayed with a deltamethrin ultra low volume formulation (Decis® UL), were utilized as hosts. In the brown locust, this insecticide elicited a curious shade seeking response followed by a protracted paralysis, which W. pachytyli flies exploited. Despite the presence of relatively high deltamethrin residues, following spraying with Decis® UL, a heavy influx of flies regularly flew into spray areas and readily larviposited on sprayed hoppers. Resultant maggots successfully completed their life cycle within such toxic hosts. Since Decis® is in widespread use or brown locust control operations in the Karoo, such an abundance of additional paralysed hosts would result in a burgeoning W. pachytyli adult fly population, thereby enhancing parasitic potential. Paradoxically, the positive side-effects reported here on the impact of locust control operations with Decis® on a non-target, beneficial agent such as W. pachytyli, provides an anomalous example of a broad-spectrum insecticide actually benefiting a natural enemy.

Two new species of soil-dwelling penthalodid mites of the genus Stereotydeus, Stereotydeus vaginatus and Stereotydeus pallodus, are described. Diagnostic descriptions of both the family Penthalodidae and the genus Stereotydeus are provided. The historical changes in the generic composition of the family Penthalodidae are discussed. An identification key to genera of the Penthalodidae and South African species of the genus Stereotydeus is proposed. Additional features, unique to species of some genera within the superfamily, are highlighted. A redefinition of the eupodoid mites, based on an analysis of recently described diagnostic features, is suggested.

Laboratory experiments on the feeding preferences of the potential predators of Musca domestica L. and Fannia canicularis (L.) indicated that Philonthus sordidus (Gravenhorst) consumed all immature stages of M. domestica while Carcinops pumilio (Erichson), Carcinops troglodytes (Paykull), Oxytelus sculptus (Gravenhorst), Alphitobius diaperinus (Panzer) and Macrocheles muscaedomesticae (Scopoli) fed on the eggs and first instar larvae of M. domestica. The predators could be important in the natural control of house flies. Predation rates at a range of predator densities varied considerably within and between species. Predation rates of C. pumilio decreased with an increase in predator density. Adult C. pumilio starved for nine days consumed significantly more M. domestica immatures than those fed for nine days. Starvation and feeding treatments had no effect on the predation rate of M. muscaedomesticae. The high numbers of eggs and young larvae consumed by C. pumilio and M. muscaedomesticae indicate that these two species have considerable potential for the biological control through augmentative releases against house flies breeding in poultry manure.

The seasonal cycles of Eriosoma lanigerum (Homoptera : Aphidiae) and its natural enemy, Aphelinus mali (Hymenoptera: Apelinidae), were studied in the Western Cape Province region of South Africa. Crawlers of E. lanigerum migrated from the roots into the apple trees during spring to initiate above-ground colonies. Population numbers peaked at the end of summer. Aphelinus mali became active from February until June. Eriosoma lanigerum numbers declined with the onset of winter but a few colonies remained on apple trees during winter.

The new species Megastigmus zebrinus Grissell is described based on specimens associated with seed capsules of Eucalyptus camaldulensis Dehnhardt (Myrtaceae), an endemic Australian tree. The wasp has been commonly collected in South Africa, where it was presumably introduced along with its host tree. It has apparently adapted to fruits of Syzygium cordatum Hochst. ex Krauss, an endemic South African tree in the same family as Eucalyptus. Observations on the gall-forming habit of Megastigmus zebrinus are presented based on dissections of Eucalyptus seed capsules. This appears to be the first species of Megastigmus that has been positively confirmed as a gall-former based on dissection of seed capsules.

Nestmate recognition in the queenless ponerine ant, Streblognathus aethiopicus, was evaluated with a behavioural bioassay. Ten pairs of nests were randomly chosen from an aggregation of 74 nests. While nestmates never showed aggression towards each other, the behaviour towards non-nestmates was either aggressive or non-aggressive, demonstrating the ability to recognize nestmates. Also, the nests in this aggregation were evenly spaced, further supporting the notion of territoriality in this species. To evaluate the relative importance of environment and genetics on the observed variation in nestmate recognition, we measured the spatial and genetic distances between nests. Workers of 13 nests were genotyped with the AFLP technique. Multiple regression analysis revealed no significant impact of spatial and genetic distance on aggressive behaviour. Thus, further studies are necessary to reveal the actual mechanisms underlying nestmate recognition in this species. Two distinct groups of nests with genetically homogeneous and heterogeneous workers were found, which may indicate gamergate replacement or colony fission.

Neoseiulus californicus has been the dominant mite predator in the Elgin district of the Western Cape Province, South Africa, since the 1994/95 season when it was first recorded. During the 2002/03 season relatively high numbers of Euseius addoensis, a local specialist pollen feeder/generalist predator, were also recorded. While N. californicus has been present, population levels of the phytophagous mites, Tetranychus urticae and Panonychus ulmi, have declined steadily. N. californicus usually appeared when there were between two and four phytophagous mites per leaf. However, during the 2001/02 and 2002/03 seasons, it was recorded before the phytophagous mites appeared. The population peak of phytophagous mites usually varied between an average of two to 13 mites per leaf, while during the 2001/02 and 2002/03 seasons the phytophagous mite population peaked at less than one mite/leaf. Prior to the appearance of N. californicus, apple orchards in the Elgin area received at least one acaricide spray per season. Acaricides are no longer used on apples. A benefit-cost analysis was conducted in the Elgin district, where there are approximately 8000 ha bearing apples. Two scenarios were analysed. In the first, the cost of acaricides was fixed during each year at R60.00/ha. In the second, the 1993 price of an acaricide was set at R250.00 and was escalated using index values for sprays and dips. In the first scenario the benefit-cost ratio was 34, 52 and 69 for a reduction of 1, 1.5 and 2 acaricides per season, respectively. In the second scenario it was 189, 284 and 378 for the same season.

The feeding behaviour of field-caught Anopheles arabiensis in the Elabered sub-zone of Eritrea was determined by direct-ELISA. Human IgG was detected in 16.9 % of the blood meal samples. The majority of mosquitoes (66.9 %) fed on cattle while the percentage of mixed human/cattle feeds was 3.8 %. Anopheles arabiensis females, obtained through different collection methods, were tested for Plasmodium falciparum and P. vivax circumsporozoite antigens using ELISA. The mean P. falciparum sporozoite rate for the three month study period was 0.68 %. None of the specimens was positive for P. vivax.

The geometrid caterpillar Isturgia deerraria was imported from Kenya into quarantine facilities in Australia as a potential biological control agent for prickly acacia, Acacia nilotica subsp. indica (Benth.) Brenan (family Mimosaceae). The insect was then tested on 30 plant species presented to neonate larvae as a no-choice cut foliage test and 13 plant species presented as a no-choice potted plant test. In these tests the insect was able to complete its life cycle on 13 native Acacia spp. and also on Acacia farnesiana and the exotic ornamental Delonix regia (family Caesalpiniaceae). The tests supported field observations that the insect has a host range spanning many leguminous species and as such the insect could not be considered for release in Australia.

The social organization of allodapine bees varies widely, both between and within species, providing considerable material for comparative approaches to studying the evolution of sociality. Within the Allodapini, Macrogalea is the sister clade to all other extant allodapine species and is also morphologically the most primitive. Based on studies of two African species of Macrogalea, sociality has been assumed to be an ancestral trait for the entire tribe. We tested this assumption with the study of two species from Madagascar. Using nest content and dissection data, the social organization of two previously unstudied allodapine species, Macrogalea Ramena sp. and Macrogalea ellioti, were examined. The data suggest M. Ramena sp. and M. ellioti are both social, and although their social behaviour is less complex than the African species, phylogenetic conservatism is present within the Macrogalea. The form of sociality exhibited by Macrogalea is more primitive than that of other allodapines, with a more complex sociality possibly contributing to the success of these other allodapine clades.

The compilation of a catalogue of Afrotropical bees has necessitated the publication of 359 new combinations. These were implied by changes in the generic classification made previously, but for which the new species names were never published. Homonymy resulted in five new names being proposed: Sphecodes punctiscutum Eardley & Urban, Heriades otavicus Eardley & Urban, Megachile manyara Eardley & Urban, Megachile mimeticana Eardley & Urban, Megachile mixtura Eardley & Urban.

Nest and nestmate recognition cues were investigated in the primitively social South African allodapine bee, Allodape rufogastra. Nest owners were able to distinguish between resident and non-resident bees, and engaged in significantly more agonistic interactions with non-residents. Combined GC-MS analysis of extract of head extracts showed it to contain a series of fatty acids and long-chain hydrocarbons. The relative abundances of compounds differed between individuals, suggesting that secretions from the head may partially serve as a nestmate recognition cue. Bees were also able to distinguish their nests from conspecific nests. Combined GC-MS of extracts taken from nest collars revealed nest-specific blends of compounds that would facilitate nest identification and discrimination. Recognition of nestmates and the home nest are important precursors to more sophisticated social interactions and communal organization.

The bioecology of the cowpea pod weevil, Piezotrachelus varius, and post-harvest seed losses were studied in the laboratory and in cowpea fields in the Western Highlands of Cameroon during the first and second cropping seasons of 1999 and 2000. Adult weevils appeared before flowering and fed on cowpea leaves and flowers before switching to newly formed pods. Pod-feeding produced holes on the pod wall mesocarp through which the female layed a cluster of 2-5 ovoid, semi-translucent eggs; the eggs hatched 3-4 days later. Three larval stages fed on the peas and pupated within the pod, usually near the damaged peas. Juveniles continued to feed in the mature harvested cowpea pods in storage; adults emerged up to two weeks after harvest. Development was completed within 16-17 days and the adults lived for more than five months. Post-harvest cowpea seed damage peaked two weeks after harvest. A number of hymenopterous parasitoids, Anisopteromalus calandrae Howard, Pteromalus sp. (Hymenoptera, Pteromalidae), Pediobius sp., Aprostocetus sp. (Hymenoptera, Eulophidae) and Bracon sp. (Hymenoptera, Braconidae) emerged from the pods. These were collected and appeared to be potential parasitoids of P. varius. During the off-season for cowpea, P. varius adults survived on cowpea haulm residue left in the field and on surrounding cultivated and indigenous alternate hosts. The implication of this bio-ecological information in the management of P. varius populations is discussed.